Commit graph

8 commits

Author SHA1 Message Date
Simon Glass
20edd1ac7a tegra: spi: Support slow SPI rates
Use the oscillator as the source clock when we cannot achieve a low-enough
speed with the peripheral clock. This happens when we request 3MHz on a SPI
clock, for example.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
2015-06-09 09:56:13 -07:00
Simon Glass
635c2515c3 tegra: spi: Drop the claim_bus() method to correct delays
At present the driver does not properly honour the requested SPI CS
deactivation delay since the SPI bus is changed in the claim_bus() method.

Everything the claim_bus() method does can be done when the device is probed
(setting the speed and mode) and at the start of a new transfer (where the
fifo_status is already cleared). So drop this method.

Also, until the delay is complete, we should not touch the bus, so make sure
that spi_cs_activate() is called before other things are done in the xfer()
method.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
2015-06-09 09:56:13 -07:00
Simon Glass
9694b72442 dm: spi: Correct SPI claim/release_bus() methods
These methods should be passed a slave device, not a bus. This matches the
old SPI interface. It is important to know which device is claiming the bus
so passing a bus is not that useful.

Reported-by: Haikun Wang <haikun.wang@freescale.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Peng Fan <Peng.Fan@freescale.com>
Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
2015-04-23 15:23:45 +05:30
Simon Glass
19a25f672c dm: spi: Move the per-child data size to the uclass
This is common to all SPI drivers and specifies a structure used by the
uclass. It makes more sense to define it in the uclass.

Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
2015-01-29 17:09:55 -07:00
Simon Glass
fda6fac39b dm: tegra: spi: Convert to driver model
This converts the Tegra SPI drivers to use driver model. This is tested
on:

- Tegra20 - trimslice
- Tegra30 - beaver
- Tegra124 - dalmore

(not tested on Tegra124)

Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
2014-10-22 10:36:52 -06:00
Yen Lin
60acde43d7 spi: tegra: clear RDY bit prior to every transfer
The RDY bit indicates that a transfer is complete. This needs to be
cleared by SW before every single HW transaction, rather than only
at the start of each SW transaction (those being made up of n HW
transactions).

It seems that earlier HW may have cleared this bit autonomously when
starting a new transfer, and hence this code was not needed in practice.
However, this is generally a good idea in all cases. In Tegra124, the
HW behaviour appears to have changed, and SW must explicitly clear this
bit. Otherwise, SW will believe that transfers have completed when they
have not, and may e.g. read stale data from the RX FIFO.

Signed-off-by: Yen Lin <yelin@nvidia.com>
[swarren, rewrote commit description, unified duplicate RDY clearing code
and moved it right before the start of the HW transaction, unconditionally
exit loop after reading RX data, rather than checking if TX FIFO is empty,
since it is guaranteed to be]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
2013-12-19 00:00:51 +05:30
Axel Lin
d6f64d4a11 spi: tegra114_spi: Convert to use spi_alloc_slave()
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Marek Vasut <marex@denx.de>
Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
2013-06-13 22:55:24 +05:30
Allen Martin
77c42e80b9 tegra114: add SPI driver
Add driver for tegra114 SPI controller.  This controller is not
compatible with either the tegra20 or tegra30 controllers, so it
requires a new driver.

Signed-off-by: Allen Martin <amartin@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
2013-03-25 09:56:07 -07:00